Thermally stable aryloxybenzimidazobenzophenanthroline compositions

ABSTRACT

Thermally stable aryloxybenzimidazobenzophenanthroline polymer compositions are synthesized by the condensation of a tetraamino bisaryloxy compound with an aromatic tetracarboxylic acid or dianhydride thereof. The high thermal stability of the polymers and their solubility in a variety of organic solvents render them especially suitable for use in high temperature applications such as in fabrication of plastic composites and protective coatings.

ied States l5 tent 1 Arnold et a1.

[ Dec. 9, 1975 THERMALLY STABLE ARYLOXYBENZIMIDAZOBENZOPHENAN- THROLINE COMPOSITIONS Inventors: Fred E. Arnold, Centerville, Ohio;

John G. Breland; Frank W.

Villaescusa, both of Colorado Springs, Colo.

Assignee: The United States of America as represented by the Secretary of the Air Force, Washington, DC

Filed: May 30, 1974 Appl. No.: 474,562

US. Cl..." 260/47 CP; 117/161 P; 260/30.8 R; 260/30.8 DS; 260/32.6 N; 260/33.4 P;

Int. Cl. COSG 73/20 Field of Search 260/47 CP, 49, 50, 78 TF, 260/65 References Cited UNITED STATES PATENTS 12/1968 Paufler 260/47 3,681,284 8/1972 Grundschober et a1. 260/47 3,740,410 6/1973 Gerber 260/295 3,743,624 7/1973 Arnold et a1 260/47 3,792,024 2/1974 Saferstein 260/78 3,798,201 3/1974 Saferstein et a1. 260/78 Primary Examiner-Lester L. Lee Attorney, Agent, or FirmJoseph E. Rusz; Cedric H. Kuhn [57] ABSTRACT 6 Claims, 2 Drawing Figures US. Patant Dec. 9, 1975 Sheet 1 0f 2 3,925,311

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U.S Patent Dac. 9, 1975 Sheet 2 of 2 Wo sey .mswm

THERMALLY STABLE ARYLOXYBENZIMIDAZOBENZOPHENANTHRO- LINE COMPOSITIONS RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured and used by or for the Government of the United States for all governmentalpurposes without the payment of any royalty.

FIELD OF THE INVENTION This invention relates to polymeric material which possesses a high degree of thermal stability. In one aspect it relates to a process for synthesizing the polymeric materials.

BACKGROUNDOF THE INVENTION as in the fabrication of nose cones and heat shields for space vehicles, rocket engine components, and the like. Because of their thermal stability, the aromatic, hetero cyclic polymers have been found to be particularly useful in aerospace applications. Unfortunately, the fused and highly aromatic nature of these ring systems, which give them their exceptional stability, tends to render them intractable.

It is an object of the present invention, therefore, to provide improved thermally stable, aromatic, heterocyclic polymers.

Another object of the invention is to provide thermally stable polymeric materials which are soluble in common aprotic solvents.

A further object of the invention is to provide a process for synthesizing the polymeric materials of high thermal stability.

Other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the ensuing disclosure and FIGS. 1 and 2 of the drawing that show graphs of data demonstrating the thermal stability of the polymer compositions.

SUMMARY OF THE INVENTION This invention resides in a thermally stable polymer which consists essentially of repeating units having the following formula:

Ar 0 I wherein Ar is 1e; @rnli' There are generally at least 2 and preferably at least 4 tion, a considerable excess results in the production of of the recurring units in the polymer. In general, the lower molecular weight products. number of recurring units is such that the polymer has Examples of aromatic tetracarboxylic acids (Formula an intrinsic viscosity [n] of about 0.30 to 1.0 as deter- III) which can be used include 1,4,5 ,8-naphthalenetetmined in methane sulfonic acid. racarboxylic acid; 4,4'-dinaphthalic acid; 3,4,9,.10-

In one embodiment, the present invention resides in perylene tetracarboxylic acid; pyromellitic acid; a process for preparing the aryloxybenzimidazobenzo- 3,4,3,4-diphenyloxi detetraacid; 3 ,4,3,4-benzophenanthroline polymers. Thus, the polymers are synphenonetetracarboxylic acid; l,2,5,6-naphthalenetetthesized by the condensation of a tetraamino bisaryloxy racarboxylic acid; 2,2',3,3-diphenyltetracarboxylic compound with an aromatic tetracarboxylic acid or a acid; pyrazine-2,3,5,6-tetracarboxlic acid; thiophenecorresponding dianhydride. The condensation reaction 2,3,4,5-tetracarboxylic acid; and the like. The correinvolved is illustrated by the following equation: sponding dianhydrides of the aforementioned carbox- (II) (III) (IV) Polymer of Formula (I) In the above equation, Ar and Ar are as indicated ylic acids are examples of compounds of Formula IV hereinabove and R is z 0r 3 3 5 that can be used. It is often preferred to employ the di- The condensation reaction shown by the above equah d id particularly l,4,5,8-naphthalenet t 'tion is Conducted under an inert aiihospheiie ih p yboxylic acid dianhydride and 4,4'-dinaphthalic acid di- P P acid or in a fused inorganic salt, such as anhydride. The aromatic tetracarboxylic acids and timony trichloride OI bismuth trichloride. When utiliztheir corresponding dianhydrides are we kn wn com ing polypho phori acid as the reaction madium, the 40 pounds which are described in the literature. condensation reaction is usually carried out at a tem- The tetraamino bisaryloxy Compounds of Formula II, Perature ranging from about 1000 o 5 for a period used as monomers in synthesizing the polymers of this of about 5 to 20 hours' The reaction is generally invention, are new compositions of matter. Examples ducted at a temperature ranging from about 60 to of these compounds include l,3 bis(34 diamino 180C for a Period of about 5 to 20 hours h m phenoxy)benzene; l,5-bis(3,4-diaminophenoxy)naphploying a fused salt as the reaction medium. WllllC high thalene; 2,2' biS(3,4 diaminophenoxy)biphenyl; 4 4- molecular weight weight polymers are obtained when his(3Adiaminohhenoxy)diphenyl lf 4 4' using either type of solvent, it is often preferred to conbi (3 4 di i h lfid 4 4' 3 4 i duct the reaction in a fused salt, utilizing a dianhydride phenoxwether; 44I bis(3,4 diaminophenoxy) as one of the reactants. This is because the fused salts methane; and the In the exemplary compoundshot Poiyiheric as is P yp p acid, thereby corresponding to Formula II, the R radicals are NI-I obviating any difficulty in stirring the reaction medium However the corresponding tetraamino h hl and concomitantly permitting higher concentrations of rides he R f Formula [I i NHsCl, can also be reactants. Furthermore, the dianhydrides have a longer ployed as mentioned i b shelf-life and can be obtained in a higher purity than As Seen f Formula 11 the compounds the tetraacids. However, when a tetraamino hydrochlodi th t c nt i aromatic ether linkages.

ride is used Of a reactants, a pa P When the compounds undergo a condensation reaction FOfmllla II In Whlch R 15 a p yp p acid with an aromatic tetracarboxylic acid or a dianhydride must be used as the reaction medium This is necessary thereof, the ether linkages impart several sites for bond in Order that the amino hydrochloride groups y he rotation within the polymer chains, thus improving solconverted to reactive amino groups by evolution of hyubility parameters. Thus, the polymers are soluble in drogen chloride. common aprotic solvents such as m-cresol, m-methoxy- Any suitable inert gas can be used in the practice of phenol, dimethyl sulfoxide, dimethyl formamide, and the process. Examples of such gases include nitrogen, the like. On the other hand conventional aromatic, hethelium, argon, and the like. erocyclic polymers are generally soluble only in con- In preparing the polymers of this invention as decentrated sulfuric acid. As a result the polymers are scribed above, the monomers are usually employed in rendered more processable, thereby alleviating the equimolar amounts. While a slight excess of one of the problem of intractability of conventional aromatic, hetmonomers is not detrimental to the condensation reacerocyclic polymers.

5 The tetraamino bisaryloxy compounds are synthesized by what can be termed a two step procedure. In the first step, tetranitro aryl ether compounds are prepared by aromatic nucleophilic substitution of various aryl diols with 4-f1uoro-1,2-dinitrobenzene. The reaction involved is illustrated by the following equation:

2 F Bose NO +HOAFDOH Solvent 3 N 2 O Ar N0 In this equation Ar is as indicated hereinabove. After recovery and purification of the tetranitro aryl ether compound, it is converted in the second step to the tetraamino bisaryloxy compound. This is accomplished by reduction of the tetranitro aryl ether compound with hydrazine or hydrazine hydrate in the presence of a catalyst consisting essentially of palladium, platinum or Raney nickel on a charcoal support. The reaction that occurs is illustrated by the following equation:

. Hydrazine 5 Catalyst In the above equation, Ar is as indicated hereinabove. When it is desired'to obtain a tetraamino hydrochloride (Nl-l Cl) as the product, the tetraamino compound is contacted with concentrated hydrochloric acid. Because the tetraamino hydrochlorides are often more stable than the tetraamines, it is frequently preferred to use the former compounds in the process of this invention. In our copending application Ser. No. (Inv. No. 9838), there is a detailed discussion of the preparation of the tetraamino bisaryloxy compounds. The disclosure of this copending application is incorporated herein by reference.

In isolating the polymer product, the reaction mixture is cooled, e.g., to room temperature, at the end of the reaction period. The reaction mixture is then poured into a non-solvent for the polymer, such as an alcohol, a weak acid or water, thereby causing the polymer to precipitate from solution. After recovery of the polymer, as by filtration or decantation, it is washed, e.g., with an alcohol, a weak acid or a mixture thereof, and then dried under a vacuum at a temperature ranging from about 70 to 100C.

A more complete understanding of the invention can be obtained by referring to the following illustrative examples which are not intended, however, to be unduly limitative of the invention.

EXAMPLE I Po1y[6,9-dihydro-6,9-dioxobisbenzimidazo[2, lb: 1 2-.I]benzo [1,u.v]- [3, 8]phenanthroline-3,12-diyl)oxy-- m--phenyleneoxy] A mixture of 0.9904 g (3.25 mmoles) of l,4,5,8- naphthalenetetracarboxylic acid and 1,524 g (3.25 mmoles) of l,3-bis(3,4-diaminophenoxy)benzene hydrochloride was added to 100 ml of deoxygenated polyphosphoric acid at room temperature. The mixture was heated under a nitrogen atmosphere to C and maintained thereat for a period of 8 hours. The temperature was then gradually increased to 185C and maintained thereat for 10 hours. The product was obtained by pouring the cooled reaction mixture into one liter of well stirred methanol. After separating the precipitated product by filtration, the product was thoroughly washed with boiling methanol and dried at C under reduced pressure for 24 hours to give 1.59 g of reddish brown polymer. The polymer product had an intrinsic viscosity [n] of 0.8 as determined in methane sulfonic acid. Analysis Calcd for (C H N O (percent): C, 74.13; H, 2.72; N, 10.80

Found (percent): C, 73.73; H, 2.50; N, 10.30

EXAMPLE ll Poly[6,9dihydro-6,9-dioxobisben2imidazo[2, l-b: l 2-J-)benzo[1mn]-[3,8]phenanthroline-3,l2-diy1)oxol ,S-naphthaleneoxy] A mixture of 0.4289 g (1.59 mmoles) 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and 0.9957 g (1.59 mmoles) of l,5-bis(3,4-diaminophenoxy)naphthalene was added to 75 g of antimony trichloride. The mixture was. slowly heated to 70C, under a nitrogen atmosphere, whereupon the antimony trichloride melted and the reaction mixture became homogeneous. The reaction temperature was increased to C and maintained at that temperature for 6 hours. Acetic acid was added to the cooled reaction mixture, thereby precipitating the product as a fine brown solid. After separating the product by filtration, it was washed with boiling acetic acid, methylene chloride, and methanol. The polymer, 0.9 g (100%), had an intrinsic viscosity of 0.4 as determined in methane sulfonic acid. Analysis Calcd for (C H N O (percent): C, 76.05; H, 2.83; N, 9.86

Found (percent): C, 75.43; H, 2.46; N, 9.25.

EXAMPLE III Preparation of Poly [6,9-dihydro-6,9-dioxobisbenzimidazo[ 2, l -b: l ,-2 J ]benzo[ lmn] [3 ,8 ]phenanthroline-3 l2-diyl)oxy-l ,l biphenyl-oxy] A mixture of 0.960 g (1.27 mmoles) of 2,2-bis(3,4- diaminophenoxy)biphenyl and 0.343 g (1.27 mmoles) of 1,4,5,8-naphthalene-carboxylic acid dianhydride was added to 100 ml of deoxygenated polyphosphoric acid at room temperature. The mixture was slowly heated (8C/min) under nitrogen to C and maintained at that temperature for 10 hours. The product was obtained by pouring the cooled reaction mixture into one liter of well stirred methanol. After isolating the product by filtration, it was thoroughly washed with anhydrous methanol and dried at 80C under reduced pressure to give 0.75 g (100%) of reddish brown polymer. The polymer had an intrinsic viscosity of 0.41 as 7 determined in methane sulfonic acid. Analysis Calcd for (C H, O N (percent): C, 76.76; H, 3.05; N, 9.42

Found (percent): C, 79.43; H, 2.58; N, 8.91

EXAMPLE IV Preparation of Poly[6,9-dihydro-6,9-dioxobisbenzimidazo [2, l-B: l, 2J]benzo(1 Inn] [2. 8] phenanthroline-3,l2- diyl)oxy-4,4-diphenyl-sulfide-oxyl] 4,4-Di(3,4-diaminophenoxy)diphenyl sulfone (0.93 g, 2.08 mmoles) and 1,4,5,8-naphthalenetetracarboxylic acid dianhydride (0.5585 g, 2.08 mmoles) were added to 100 ml of deoxygenated polyphosphoric acid. The mixture was slowly heated (8C/min), under nitrogen, to 195C and maintained at this temperature for hours. The reaction mixture was cooled to room temperature and poured into 2 liters of water, thereby precipitating the product. After separating the product by filtration, it was thoroughly washed with water and dried at 80C under reduced pressure for 12 hours to give 1.28 g (94%) of a brown polymer. The polymer had an intrinsic viscosity of 0.56 as determined in methane sulfonic acid. Analysis Calcd for (C H O N S),, (percent): C, 69.29; H, 2.75; N, 8.50

Found (percent): C, 67,50; H, 2.25; N, 8.01

EXAMPLE V Preparation of Poly( 7,7 -dioxo[4,4-bi-7H-benzimidazo[2,1-a]benzo- [de]isoquinoline]-10,10-diyl)oxy-1 ,S-naphthaleneoxy] A mixture of 0.3032 g (0.814 mmole) of 1,5-bis(3,4- diaminophenoxy)naphthalene and 0.3210 g (0.814 mmole) of 4,4-dinaphthalic acid dianhydride was added to 100 ml of deoxygenated polyphosphoric acid at room temperature. The mixture was slowly heated (8C/min) to 195C and maintained at that temperature for 10 hours. The cooled reaction mixture was poured into one liter of well' stirred water, thereby precipitating the polymer. After separating the polymer by filtration, it was thoroughly washed with water and then with anhydrous methanol. The washed product was then dried at 80C under reduced pressure for 12 hours to give 0.56 g (100%) of a brown polymer. The polymer had an intrinsic viscosity of 0.35 as determined in methane sulfonic acid. Analysis Calcd for (C H N O (percent): C.79.52; H,3.l9; N,8.06

Found (percent): C,77.38; H,2.85; N,7.38

EXAMPLE VI Preparation of Poly[7,7-dioxo[4,4-bi-7H-benzimidazo [2, l-a] benzo-[de]isoquinoline]-10, 10-diyl)oxy-l,3-phenyleneoxy] A mixture of 1.0 g'(2.13 mmoles) of l,3-bis(3,4- diaminophenoxy)-benzene hydrochloride and 0.842 g (2.13 mmoles) of 4,4'-dinaphthalic acid dianhydride was added to 100 ml of deoxygenated polyphosphoric 8 acid at room temperature. The mixture was heated, under nitrogen, to C and maintained at that temperature for 8 hours. The temperature was then gradually heated to 195C and maintained at that temperature for 10 hours. The cooled reaction mixture was poured into one liter of well stirred water, thereby precipitating the product. After separating the product by filtration, it was thoroughly washed with methanol. The washed product was dried at C under reduced pressure for 24 hours to give 1.37 g of reddish brown polymer. The polymer has an intrinsic viscosity of 0.62 as determined in methane sulfonic acid. Analysis Calcd for (C H N O (percent): C,78.25; H,3.12; N,8.69

Found (percent): C,75.85; H,2.82; N,7.83

EXAMPLE VII Preparation of Poly [7,7-dioxo [4,4-bi-7H-benzimidazo [2, l-albenzo- [de]isoquinoline]-10,10-diyl)oxy- 1, 1 '-biphenyl-oxy] A mixture of 0.2884 g (0.723 mmole) of 2,2-bis(3,4- diaminophenoxy)biphenyl and 0.2854 g (0.723 mmole) of 4,4-dinaphthalic dianhydride was added to 100 ml of deoxygenated polyphosphoric acid at room temperature. The mixture was slowly heated (8C/min) under nitrogen to C and maintained at that temperature for 10 hours. The cooled reaction mixture was poured into one liter of well stirred water, thereby precipitating the product. After separation of the product by filtration, it was washed first with water and then methanol. The washed product was dried at 80C under reduced pressure for 12 hours to give 0.5 g (96%) of reddish brown polymer. The polymer had an intrinsic viscosity of 0.43 as determined in methane sulfonic acid.

Analysis Calcd for (C H N O (percent): C,79.98, H,3.35; N,7.77

Found (percent): C,77.86; H,3.78; N,6.95

The polymers of Examples I and III were subjected to thermogravimetric analysis, and the data obtained are shown graphically in FIGS. 1 and 2, respectively. As seen from FIG. 1, the polymer of Example I underwent a weight loss of 10 percent at 650C in nitrogen and 540C in air. From FIG. 2, it is seen that the polymer of Example III lost 10 percent of its weight at 550C in both air and nitrogen.

As mentioned hereinbefore, the polymers of this invention are soluble in an aprotic solvent, such as mcresol. Furthermore, thermogravimetric analysis of the polymers shows that they are thermally stable at elevated temperatures. These desirable properties render them particularly useful for high temperature applications and facilitate the fabrication of composites an the preparation of protective coatings.

As will be evident to those skilled in the art, modifications of the present invention can be made in view of the foregoing disclosure. Such modifications fall within the spirit and scope of the invention.

We claim:

1. A thermally stable polymer consisting essentially of repeating units having the following formula:

g g ne eew;

and Ar is 2. The polymer of claim 1 in which Ar is and Ar is 40 g E g 5. The polymer of claim 1 in which Ar is 3. The polymer of claim 1 in which Ar is and Ar is H Q and Ar is 6. The polymer of claim 1 in which Ar is and Ar is 4. The polymer of claim 1 in which Ar is Q Q Q Q 

1. A THERMALLY STABLE POLYMER CONSISTING ESSENTIALLY OF REPEATING UNITS HAVING THE FOLLOWING FORMULA:
 2. The polymer of claim 1 in which Ar is
 3. The polymer of claim 1 in which Ar is
 4. The polymer of claim 1 in which Ar is
 5. The polymer of claim 1 in which Ar is
 6. The polymer of claim 1 in which Ar is 